Atrial fibrillation (AF) is the most common type of cardiac arrhythmia affecting up to 2% of the population with a higher occurrence in the elderly. The first line treatment for AF is anti- arrhythmia drugs. Yet there are many side effects to these drugs and the recurrence rate of AF while patients are being treated with these drugs is well documented. The second level treatment is generally accepted as some form of thermal ablation that includes radio frequency ablation (RFA) or cryoablation. The former is often a ?point-by-point? procedure that can take a long time to accomplish successfully and can be technically challenging; whereas currently the most common cryoablation application is a ?Cryoballoon? designed such that there is a circumferential zone that achieves pulmonary vein isolation (PVI). Yet each of these thermal modalities is associated with a variety of problems such as phrenic nerve palsy (more commonly associated with Cryoballoon) and issues of unintentional heat spread (RFA) causing damage to neighboring non-targeted tissue. CPSI Biotech is a medtech company specializing in thermal ablation devices designed for the clinical market. The Company?s strategy is to develop and patent the technology and then license the intellectual property to large, global medical device companies. CPSI?s products include the Super Critical Nitrogen (SCN) and Pressurized Sub-cooled Nitrogen (PSN) cryo-engines currently designed for mono thermal cryoablation of select tissues including those of the heart, bladder, esophagus, kidney and pancreas among others. CPSI is currently developing a spot catheter cryoprobe designed to treat ventricular tachycardia ? a first of its kind NIH-supported technology. This Phase I proposal focused on AF is the second chapter of CPSI?s cardiac business strategy formulated to engineer additional devices for treating arrhythmias through the development of a mono therapy/cryoablation catheter (ICEolate) and, more importantly, a new Dual Thermal Ablation (DTA - heat and cold) device (ICEolate-DTA) to treat AF. ICEolate-DTA will be a multifunctional lasso-tipped catheter that can both heat (like RFA) and/or freeze tissue from a single catheter device. This technology will also enable application of advanced ablation protocols which utilize the application of both heat and freeze in tandem. The advantages of the ICEolate-DTA are several not the least of which is the ability to use heat followed by cold so that the heat spread into neighboring tissue can be controlled and quenched while at the same time more heat can be used for more effective and longer-lasting PVI. The Specific Aims are the following: (1) Develop ICEolate and ICEolate-DTA lasso ablation catheters; (2) Test the efficacy of the ICEolate catheters in an ex vivo model; (3) Evaluate the ICEolate catheters in pilot animal studies. In summary, the intent of this feasibility Phase I project is to design a unique DTA lasso ablation catheter. The resulting ICEolate technology will be superior to RFA and Cryoballoons given its design and DTA capabilities leading to improved thermal ablation PVI procedures for treating AF resulting in fewer risks to patients.